The invention relates to a method and a device for converting an analog input signal into a digital output signal by means of an analog-to-digital converter.
Analog-to-digital converters are known per se in practice, in a large number of different embodiments thereof.
A fundamental problem of analog-to-digital converters having semiconductor components, including analog-to-digital converters in the form of integrated semiconductor circuits, is the fact that the power consumption increases excessively when the dynamic range increases.
In modern digital hearing aids, for example, the aim is to be able to process input sound levels that are louder than the classical limit of 90-95 dBSPL, for example up to 115 dBSPL, without excessive distortion. It is not possible, however, to use a conventional semiconductor analog-to-digital converter having a dynamic range of for example 100 dB for this purpose, because of the power consumption of such an analog-to-digital converter, which is too high for use in a hearing aid.
On the other hand, it is preferable to have the processing of signals take place digitally as much as possible, in order to prevent the use of analog circuits, which are sensitive to high-frequency radiation, for example from wireless telephones, as much as possible. Furthermore, digital solutions provide greater freedom as regards the programming of parameters for optimizing signal processing.